First of all, there are more things than typed arrays (vectors) in AS3, the main thing being a consistent runtime. Also the way you structure an AS3 project is different since the language supports packages/classes etc while in JS you (for better or worse) don't have these concepts so you end up with many different code styles. Even though browsers implement the some of the features, there are subtle differences in the implementations. This results, in real world scenarios, that this stuff are being abstracted away, layers and layers of abstractions, libraries for everything. I have my doubts that this SWF interpreter can be efficient.
There are too many layers in all doomed software, whether written in JS or AS3.
Subtle differences in implementations, you say? That is called the open web. Come on in, the water's fine. Pay no attention to the drowning plugins over in that cold corner...
